In a business system or the like in operation, the execution of a job is performed at a timing scheduled in advance, for example. A job is a set of programs that are run using a resource (e.g., CPU or memory) of a computer (hereinafter also referred to as node), for example. The programs are run in coordination to obtain a processing result.
During the execution of such a job, there are cases where a node in which the job is executed needs to be changed in accordance with the situation of a resource (memory, disk, or the like) of a node executing the job, for example. In this case, an operation manager stops a process of the job executed in the node before migration and migrates information (e.g., management information of the job or information relating to a user) needed for executing the job to a node of a migration destination, for example. The operation manager resumes the execution of the process of the migrated job in the node of the migration destination. (Hereinafter, this processing is also referred to as job migration). Accordingly, it is possible to change a node in which a job is executed flexibly in accordance with the situation of a resource of a node. (For example, see Japanese Laid-open Patent Publication No. 2012-234564 and Japanese Laid-open Patent Publication No. 2011-210151.)
During the execution of a job in a manner described above, there are cases where a file system that manages data access stores accessed data into a memory within a node, in the case where access to data stored in an external storage device (hereinafter also referred to as storage device) has occurred, for example. (Hereinafter, data stored in a memory is also referred to as cache data.) Accordingly, it is possible to acquire data without accessing the storage device, in the case of accessing data that has been accessed before by a job again. Therefore, it is possible to increase the efficiency of data access by a job. In the case where a job has updated cache data, the file system synchronizes the cache data and the data stored in the storage device at a predetermined timing. Accordingly, occurrence of access to the storage device every time a job updates cache data can be prevented.
In the case of executing job migration, the file system performs processing of synchronizing cache data and data stored in the storage device before the job migration is performed. Accordingly, it is possible for the file system to provide consistency of the data before and after the execution of the job migration. A job for which job migration has been executed (hereinafter also referred to as migrated job) acquires needed data by performing access to the storage device after resuming processing.
However, in the case where the difference of cache data and data stored in the storage device is large, for example, there are cases where the completion of job migration is delayed, since it takes relatively a longer time to implement data synchronization. In the case where job migration has been executed, the migrated job needs to access the storage device again for data stored in the memory before the job migration. Thus, in the case where job migration has been executed, the efficiency of data access by a migrated job is reduced.